Effect of neuroleptics on endogenous norepinephrine in rat brain

摘要: Abstract The neuroleptic drugs clozapine, thioridazine and methiothepin, but not chlorpromazine, markedly reduced the norepinephrine (NE) levels in brain of rats kept normothermic. Clonidine prevented NE lowering effect clozapine. In animals with sectioned spinal cords, clozapine decreased only segment cranial to lesion whereas normal drug induced a similar decrease caudal part cord. After pretreatment dopamine-β-hydroxylase inhibitor FLA 63 dose which did diminish cerebral NE, chlorpromazine caused small significant this amine. It is concluded that, due blockade receptors subsequent feed-back activation neurones, methiothepin increase release such degree that amine loss cannot be fully compensated by synthesis possibly as consequence an insufficient rate β-hydroxylation dopamine. contrast, case seems relatively weak NE-receptor blocking agent, compensation still possible.